Blood perfusion involves encouraging blood through the vessels of the body. For such purposes, blood perfusion systems typically include the use of one or more pumps in an extracorporeal circuit that is interconnected with the vascular system of a patient. Many surgical procedures require or prefer temporary cessation of the heart to create a still operating field. Such procedures may thus rely upon a cardiopulmonary bypass (CPB) perfusion system that temporarily replaces the function of the heart and lungs. Examples of such procedures include the surgical correction of vascular stenosis, valvular disorders, and congenital heart defects. In perfusion systems used for cardiopulmonary bypass surgery, an extracorporeal blood circuit is established that includes at least one pump and an oxygenation device to replace the functions of the heart and lungs, respectively.
More specifically, in cardiopulmonary bypass procedures, oxygen-poor blood (i.e., venous blood) is gravity-drained or vacuum-suctioned from a large vein entering the heart or another major vein in the body (e.g., femoral) and is transferred through a venous line in the extracorporeal circuit. The venous blood is pumped to an oxygenator that provides for oxygen transfer to the blood. Oxygen may be introduced into the blood by, for example, transfer across a membrane. Concurrently, carbon dioxide is removed across the membrane. The oxygenated blood is filtered and then returned through an arterial line to the aorta, femoral, or other artery.
In many cases, an extracorporeal blood circuit includes a blood reservoir that can be used to collect, filter and de-aerate blood from a variety of different sources. For example, a blood reservoir may receive one or more of venous blood from a large vein, vent blood that is collected within the heart and cardiotomy or suction blood that is collected from outside the heart but within the surgical field.